This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Mutations in human copper-zinc superoxide dismutase (SOD1) are linked to an inherited form of amyotrophic lateral sclerosis (ALS). Spinal cords of transgenic mice expressing these human S proteins contain inclusions of the human mutant proteins, but endogenous mouse SOD1 is not f as a component of these aggregates. Two sequence elements in the human enzyme have bee identified that seem to enhance its aggregation relative to the mouse enzyme. These sequence elements are under study as part of SOD1 chimeras containing mouse and human sequences.